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Summary of the HFS Working Group

Summary of the HFS Working Group. Pavel Nadolsky Claudia Glasman Steve Maxfield. This talk: Part I: Experimental Aspects (PartII: Theory aspects – Pavel Nadolsky). ~40 talks covering wide range of Hadronic Final State physics Obviously impossible to do justice to them all

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Summary of the HFS Working Group

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  1. Summary of the HFS Working Group Pavel Nadolsky Claudia Glasman Steve Maxfield This talk: Part I: Experimental Aspects (PartII: Theory aspects – Pavel Nadolsky) ~40 talks covering wide range of Hadronic Final State physics Obviously impossible to do justice to them all Will try to provide snap-shot of the various analyses Apologies in advance for leaving out ‘favourite’ results Please look at the wealth of detail in the full presentations DIS 2005 Stephen Maxfield Liverpool

  2. Puzzling Pentaquarks • New studies from H1, ZEUS, HERMES, BABAR and CLAS. • Strange and Charm pentaquark at HERA • HERMES q+, q++ and X-- • BABAR q+, q++, X– and X0 • CLAS q+  DIS 2005 Stephen Maxfield Liverpool

  3. Strange Pentaquark H1 and ZEUS ZEUS  …but is there really a contradiction? H1  DIS 2005 Stephen Maxfield Liverpool

  4. Both experiments have taken a closer look… ZEUS Zhenhai Ren DIS 2005 Stephen Maxfield Liverpool

  5. H1: extraction of upper limit for q+ cross section Christiane Risler Comparison with ZEUS: DIS 2005 Stephen Maxfield Liverpool

  6. Charm Pentaquark at HERA Karin Daum /Yehuda Eisenburg Seen by H1… H1 Preliminary: …but negative results (in different processes) from ALEPH, FOCUS, CDF, BELLE …and ZEUS same process DIS 2005 Stephen Maxfield Liverpool

  7. ZEUS have performed a careful evaluation of upper limits… Yehuda Eisenberg MC normalised to qc/D* = 1% 95% C.L. upper limit on R(qcD*p/D*) in D* window R<0.23% (0.35% for DIS)0.37%(0.51%) acceptance corrected DIS 2005 Stephen Maxfield Liverpool

  8. H1 More detailed look taken…. vs Event kinematics, D* and D*p variables < Example DIS 2005 Stephen Maxfield Liverpool

  9. HERMES pentaquark searchesAvetik Airapetian Previously published result: • Check q+ for • Kinematic reflections, detector acceptance cuts. Is it a S*+, Still there with additional p? DIS 2005 Stephen Maxfield Liverpool

  10. Searches for Pentaquarks at BaBarEric Eckhart Inclusive searches for q+(in e+e- and electro-production), X--, X0 x-y location of pKs vertices  electro-, hadro-production off detector material Electro-production only DIS 2005 Stephen Maxfield Liverpool

  11. e+e- Conclusions: DIS 2005 Stephen Maxfield Liverpool

  12. New results from CLASMarco Battaglieri • To come: • More channels • Higher energy run c.f. DIS 2005 Stephen Maxfield Liverpool

  13. Conclusions on Pentaquark results: This slide deliberately left blank DIS 2005 Stephen Maxfield Liverpool

  14. Perturbative QCD and Jets  DIS 2005 Stephen Maxfield Liverpool

  15. Precision Measurements ofaS Claudia Glasman • Review of aS determinations from H1 and ZEUS experiments. • Evaluation of HERA averages of aS(MZ) and scale dependenceofaS. Most precise determinations used in averages DIS 2005 Stephen Maxfield Liverpool

  16. Averaging must take proper account of correlations in e.g • Energy-scale uncertainties, PDFs, hadronisation corrections, terms beyond NLO Combined running of as using correlation method for data at similar ET …Next steps will need NNLO DIS 2005 Stephen Maxfield Liverpool

  17. Inclusive jet and dijets from D0Brian Davies • Run II has ~0.7 fb-1 (~half being analysed here) • Increased beam energy  extended pT reach promising sensitivity to gluon at high x • New cone algorithm IR safe • Dominant experimental systematic from jet energy scale (~5%) – still understanding new detector components • Also looking at flavour tagging of jets with ms (vertex tagging to come) and f decorrelations DIS 2005 Stephen Maxfield Liverpool

  18. Jet measurements at CDFRick Field • Now using kT • RDF preferred procedure for data/theory comparison • Future-proofing your results DIS 2005 Stephen Maxfield Liverpool

  19. CDF Inclusive b-jet cross-section Use shape of secondary vertex mass as discriminator * For CDF underlying event studies -> Pavel DIS 2005 Stephen Maxfield Liverpool

  20. Jet Production at High Q2 (H1)Thomas Kluge • Measure 2- and 3-jet cross sections at high Q2 - 150 < Q2 < 15000 GeV2 • Use to make aSdetermination Highest bin needs electroweak corrections from Z exchange. Not used DIS 2005 Stephen Maxfield Liverpool

  21. Measure cross section ratio R3/2 • Reduced experimental and theory uncertainties (e.g. mR dependence reduced to ~5%) DIS 2005 Stephen Maxfield Liverpool

  22. Inclusive Jet Cross-Sections in Neutral Current DIS Events Using the Breit FrameJeff Standage New measurement with 1999/2000 ZEUS data • Data points consistent with NLO prediction within the uncertainties. • This measurement is directly sensitive to value of s(Mz) and the scale dependence of s. • Consistent with NLO predicted ~10% increase in cross-section DIS 2005 Stephen Maxfield Liverpool

  23. Colour dynamics in photoproduction of jets (ZEUS) Juan Terron Use angular variables to distinguish the different processes DIS 2005 Stephen Maxfield Liverpool

  24. Colour dynamics in photoproduction of jets (ZEUS) Juan Terron Different shapes. e.g. a23 CFCA very different. But only 10%contribution predicted in SU(3) Fixed order calculations (Klasen, Kleinwort, Kramer) based on various symmetry groups. Consistent with SU(3) New variables needed (esp. for senstivity to 3-g vertex) DIS 2005 Stephen Maxfield Liverpool

  25. Event shapes from ZEUSAdam Everett • Choose IR- and collinear-safe event shape variables. • Compare with NLO + power corrections (Dokshitzer, Webber) (+ resummation for differential distributions) 1/n dn/dF Higher order process Calculations LO for this DIS 2005 Stephen Maxfield Liverpool

  26. Neutral and Charged Kaon Bose-Einstein Correlations in DIS Anna Galas r = source size ZEUS DIS 2005 Stephen Maxfield Liverpool

  27. Azimuthal Asymmetries in DIS (ZEUS)Artur Ukleja BGF New method: use Energy Flow Objects (weight particle directions by their energy) (better pQCD behaviour) QCDC DIS 2005 Stephen Maxfield Liverpool

  28. Measurement of Forward Jet Production at low x in DIS (H1) Albert Knutsson DIS 2005 Stephen Maxfield Liverpool

  29. Inclusive Forward Jet production in DIS (ZEUS) Nicolai Vlasov Different way of estimating scale uncertainty? DIS 2005 Stephen Maxfield Liverpool

  30. Prompt Photon Cross section in Photoproduction (H1) Josef Ferencei Use combination of shower shape variables to discriminate against p0,h NLO does reasonably well (better with jet) DIS 2005 Stephen Maxfield Liverpool

  31. Charged multiplicity distributions (ZEUS)Michele Rosin Breit Frame analysis of multiplicities Careful look at: current region in B.F.  one e+e- hemisphere Photon region in HCM mostly target region in BF DIS 2005 Stephen Maxfield Liverpool

  32. Fragmentation Process in HERMESBino Maiheu • Flavour separated multiplicity distributions – RICH • Test factorisation and validity of e+e- FFs down to low Q2 (2.5GeV2) • Must cope with low HERMES acceptance Systematics from RICH DIS 2005 Stephen Maxfield Liverpool

  33. Polarization and Asymmetries in Neutral Strange Particle Production (ZEUS)Andrew Cottrell • Strange quark polarisation (origin of s) • Baryon/meson ratio • Baryon number (how transferred?) • Conclusions: • Transverse L pol consistent with 0 • Longitudinal also – sensitivity for HERAII • No L-Lbar asymmetry – starts to limit baryon number transport models • Baryon/Meson ratio between e+e- and Heavy Ion - strong decrease with x c.f. Ariadne DIS 2005 Stephen Maxfield Liverpool

  34. p0, h and direct g production in Au+Au and p+p collisions PHENIX Terry Awes Partons from hard scattering exit through dense strongly interacting medium  “jet quenching” Au-Au with p+p Nuclear modification factor p0 and charged hadrons exhibit: Strong suppression  high gluon densities and energy densities Suppression increasing with overlap (so with increasing density and pathlength But must distinguish initial state effects – modifications to PDFs (shadowing, saturation etc) From final state effects of QGP (+etc) So look at direct g production – once produced escape unscathed DIS 2005 Stephen Maxfield Liverpool

  35. No suppression seen! Strong confirmation hadron suppression due to QGP rather than PDF modification DIS 2005 Stephen Maxfield Liverpool

  36. Jet properties from di-hadron correlations in pp and dAu PHENIXJiangyong Jia • Access properties of dijet system through 2-particle correlation in Df Relatively insensitive to multiplicity and limited PHENIX acceptance Look at Jet shape, yield, underlying event. e.g. Jet yield  …showing pp, dAu agree within errors. DIS 2005 Stephen Maxfield Liverpool

  37. Conclusion • Experimental studies of the hadronic final state alive and active • Developments in “traditional” jet cross-section and QCD studies. • New and exciting results from JLAB and RHIC • Still huge amount to learn before (and after) LHC turns on Many thanks to all the HFS speakers! DIS 2005 Stephen Maxfield Liverpool

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